Mechanical stripping apparatus

ABSTRACT

Apparatus to remove an insulating copy sheet from a moving photoconductive surface, the copy sheet being electrostatically tacked to the surface prior to removal by a corona discharge device during a xerographic image transfer operation. A stripping finger is arranged to lift the leading edge of a sheet being advanced on the photoconductive surface and to direct the sheet upwardly away from the surface. A stationary transport having a smooth flat platen to receive a stripped copy sheet in sliding relation therewith is positioned to intercept the leading edge of the stripped sheet and direct the sheet towards a subsequent processing station. Suction ports in the platen located behind the point of contact of the leading edge of the sheet lift the body of the sheet from the stripper finger and hold the sheet in sliding contact with the platen. Lifting means raise the stripper finger away from the moving surface and further stripping of the sheet is accomplished as the sheet slides along the platen and is lifted from the drum surface.

United States Patent [72] Inventor William K. Stillings PrimaryExaminer-Harvey C. Hornsby Penfield, N.Y. Assistant Examiner-Bruce H.Stoner {2 l] Appl. No. 838,902 Attorneys-Paul M. Enlow, Norman E.Schrader, James J. [22] Filed July 3, 1969 Ralabate, Ronald Zibelli andThomas J. Wall [45] Patented May 18, 1971 [73] Assignee XeroxCorporation Roche5ter,N.Y, ABSTRACT: Apparatus to remove an insulatingcopy sheet from a moving photoconductive surface, the copy sheet beingelectrostatically tacked to the surface prior to removal by a coronadischarge device during a xerographic image transfer [54] MECHANICALSTRIPPING APPARATUS operation. A stripping finger is arranged to liftthe leading 13 Claims 5 Drawing ES edge of a sheet being advanced on thephotoconductive surface and to direct the sheet upwardly away from thesurface. A [52] US. Cl tationary transport having a smooth flat platento receive a 2 stripped copy sheet in sliding relation therewith ispositioned [51] II). Cl .l 15/08 to intercept the leading edge of theheet and direct [50] Fleld 0 Search 271/51, 80, the sheet towards aubsequent processing station Suction P 1 l0, 12, 14 ports in the platenlocated behind the point of contact of the [56] R f cud leading edge ofthe sheet lift the body of the sheet from the e erences stripper fingerand hold the sheet in sliding contact with the UNITED STATES PATENTSplaten. Lifting means raise the stripper. finger away from the 2,895,5527/1959 Pomper etal 271/74X moving surface and further stripping of thesheet is accom- 3,2l5,056 l 1/1965 Campbell 271/74X plished as the sheetslides along the platen and is lifted from 3,459,477 8/1969 Anthes355/12 the drum surface.

Q 79 54 52 7 a0 24 32 a Q 50 5/ Q 9 o s ATENTE U HAY18 97 SHEET 1 or I II I I 2 7 I. 0 Wm km o Tmsfi v v TORNEY PATENTEU MAY 1 8 I97! SHEET 2 BF3 FIG. 2

MECHANICAL STRIPPING APPARATUS This invention generally relates toxerography, and, in particular, to apparatus for stripping a finalsupport material having an electrostatically transferred toner imagethereon from a moving photoconductive surface.

More specifically, this invention relates to apparatus which isparticularly well adapted to removing an insulating copy sheet having anelectrostatically transferred toner image loosely adhered thereto fromthe top surface of a moving photoconductor.

In conventional xerography, a photoconductive surface is unifonnlycharged and the charged surface then exposed to a light image of anoriginal to be reproduced. Under the in- 'fluence of the light image,the charge on the surface is selectively dissipated to produce what isknown as a latent electrostatic image. The charged latent image isdeveloped, or made visible, by attracting oppositely charged tonerparticles, which are brought into close proximity to the plate surface,into the image areas. The developed image is then generally transferredto a final support material and the image affixed thereto to form apermanent record of the original document.

An insulating material, such as paper, is more conveniently utilized asthe final support material in the xerographic art. The copy sheet isplaced over the image bearing photoconductive surface and the backsideof the sheet subjected to a spray of ionized air. A charge is built upon the sheet having a magnitude and polarity sufficient toelectrostatically attract the toner particles from the photoconductivesurface to the copy sheet. However, during transfer, a charge oppositeto the charge found in the nonimaged areas on thedrum surface is inducedin the paper causing the copy sheet to become electrostatically tackedto the drum surface. Removal of the copy sheet and the toner imageloosely adhering thereto has long been a problem in the xerographic art.

Mechanical strippers have been employed with varying degrees of successto remove copy sheets from a moving photoconductive surface in automaticxerographic reproducing apparatus. Probably one of the best known andmost widely used of these devices is the mechanical air puffer. Thepuffer is generally positioned to operate on an inverted photoconductivesurface, as for example, the bottom portion of a xerographic drum. Thecopy sheet is stripped from the surface by introducing a stream of airbetween the copy sheet and the surface and then allowing the sheet tofall away from the photoconductor where it can be picked up bysubsequent forwarding means. Because of the volume and velocity of theair stream required to perform the stripping operation, puffing devicesare inherently noisy and therefore undesirable. Furthermore, puffingdevices have been found to be dirt producing in that the air streambroadcasts'loose toner particles throughout the automatic reproducingapparatus. In some instances working parts of the machine have becomecontaminated by a buildup of this residual resin based material.

However, perhaps the most serious drawback associated with mechanicalpuflers and other mechanical strippers known in the art is the fact thatthey are best utilized when operating on an inverted photoconductivesurface. Although this relationship is the most efiicient from a sheetstripping standpoint it is nevertheless undesirable from a practicalstandpoint because it severely limits where the various xerographicprocessing stations can be positioned. For example, in a drum-typexerographic machine, paper stripping operations heretofore have beenlimited to the lower relatively inaccessible 6 oclock drum positionrather than more desirable I2 oclock drum position, therebynecessitating theuse of long and torturous paper paths and complexhandling equipment.

Electrostatic stripping, a method of stripping in which theelectrostatic tacking forces holding the support material to thephotoconductive surface are eliminated or neutralized by subjecting thesupport material to a second corona discharge of sufficient magnitudeand polarity to overcome the electro' static bond holding the sheets tothe photoconductive surface technique, the insulating copy sheet,loosely supporting a transferred toner image, is moved past a detackingcorotron. After the electrostatic charge bonding the sheet to the drumis neutralized, the copy sheet is allowed to fall under the forces ofgravity away from the photoconductive surface. The sheet is then pickedup by forwarding means and advanced to a subsequent processing station.Here again, in order to effectively remove the sheet and prevent imagedegredation, the operation must be performed while the photoconductor isin an inverted position so that the copy sheet does not fall back intocontact with the photoconductive surface.

It is therefore a primary object of this invention to improve apparatusfor removing an electrostatically tacked image bearing support materialfrom a moving photoconductive surface.

It is a further object of this invention to improve apparatus forremoving an electrostatically tacked copy sheet from a movingphotoconductive surface whereby the copy sheet may be removed when thesurface is in any position.

Yet another object of this invention is to improve sheet strippingapparatus whereby a copy sheet can be readily removed from the upperportion of a rotating xerographic drum surface.

A still further object of this invention is to reduce the dirt level inautomatic xerographic machines.

These and other objects as well as other further features of V thepresent invention are attained by means of a thin wedgeshaped stripperfinger riding in contact with a moving photoconductive surface and beingarranged so that the apex of the wedge moves between the surface and acopy sheet electrostatically tacked thereto to lift the leading edge ofthe sheet and direct the sheet away from the moving surface, astationary transport having a flat smooth working surface thereonsupported in close proximity to the stripper and positioned to interceptthe leading edge of a stripped sheet and direct the sheet towards asubsequent processing station, vacuum means arranged to pull thecontacting sheet away from the stripper finger to hold the sheet inintimate contact with the platen wherein further movement of the surfacecauses the sheet to slide along the platen and to be pulled from thesurface, and means to remove the stripper finger from contact with thephotoconductive surface.

For a better understanding of the present invention as well as otherobjects and further features thereof, reference is had to the followingdetailed description of the invention to be read in connection with theaccompanying drawings, wherein:

FIG. I illustrates schematically an automatic xerographic reproducingapparatus employing a preferred embodiment of the paper strippingapparatus of the present invention;

FIG. 2 is a partial side elevation in section of the stripping mechanismshown in FIG. 1 illustrating the leading edge of a copy sheet beinglifted from a rotating drum surface;

FIG. 3' is a partial side elevation in section of the strippingmechanism shown in FIG. 1 illustrating a copy sheet being advanced alongthe stationary transport and showing the stripping finger moved out ofcontact with the rotating drum surface;

FIG. 4 is a partial perspective view illustrating the stripping fingersupport and lifting mechanism;

FIG. 5 is a sectional view illustrating the internal construction of thestationary transport.

As shown, the automatic xerographic reproducing apparatus comprises axerographic plate including a photoconductive layer of a light receivingsurface 10 placed on a conductive backing and formed in the shape of adrum, generally designated 11, which is joumaled for rotation in theframe of the machine (not shown) about the horizontal axis of shaft 12.The xerographic plate is rotated in the direction indicated to cause aphotoconductive surface to pass sequentially through a plurality ofxerographic processing stations.

For the purposes of the present disclosure, the several xerographicprocessing stations in the path of movement of the has been used withsome degrees of success. In this stripping drum surfacemay be'describedfunctionally asfollows:

a charging station A, in which a uniform electrostatic charge isdeposited on the photoconductive layer on the xerographic drum; anexposure station B, wherein light or radiation pattern of an originaldocument to be reproduced is projectedonto the drum surface to dissipatethe charge found thereon in the exposed areas to form a latentelectrostatic image;

a development station C, at which a xerographic developing materialhaving toner particles possessing an electrostatic charge opposite tothe charge found on the drum surface in the latent image areas arecascaded over the moving drum surface whereby the toner particles adhereto the electrostatic latent image thus making the image visible in theconfiguration of the original document to be reproduced;

a transfer station D, in which the xerographic powder image iselectrostatically transferred from the drum surface to a .final supportmaterial and the final support material removed from the drum surface;and, v

a drum cleaning and toner collecting station E. wherein the drum surfaceis first treated with corona and then wiped with a doctor blade toremove any residual toner particles remaining thereon after imagetransfer and collected for reuse in the xerographic process and whereinthe drum surface is exposed to an incandescent panel to effectsubstantially complete discharge of any residual electrostatic chargeremaining thereon.

In this preferred embodiment, the charging station is preferably locatedat near the bottom or 6 o'clock drum position which is generallyreferenced A in FIG. ll. The charging arrangement consists of a coronacharging device 13 including a corona discharge array of one or morecorona discharge electrodes extending transversely across the drumsurface and which are energized from a high potential source (notshown). The corona discharge electrode is substantially enclosed withina shielding member and is adapted to generate a charge confined to thespecific exposure area.

Next subsequent thereto in the path of travel of the xerographic drum isan exposure station B wherein a flowing light image of a stationaryoriginal is placed on the moving drum surface. Basically the opticalscanning and projecting assembly comprises a stationary transparent copyboard M adapted to support the original to be copied, an illuminatingmeans LMP-l to uniformly illuminate the original supported on the copyboard, an optical scanning system including an object mirror 16 and animage mirror l8 having lens 17 and being arranged in light projectingrelationship with the moving drum surface to project successiveincremental areas of the original onto the drum surface. The lenselement is positioned beneath the copy board and is arranged to movethrough a path of travel parallel to the plane of the copy board wherebythe subject image of the original is scanned in timed relation to themovement of the light receiving drum surface.

Next adjacent to the exposure station is a de\ eloping station C inwhich is positioned developing apparatus 20 including a housing 28having a lower sump portion therein capable of supporting a quantity oftwo-component developer material. A bucket-type conveyor 27, having anysuitable drive means associated therewith, is employed to carry thedeveloper material from the sump area to the upper part of the developerhousing where it is deposited into hopper 29. The developer materialmoves downwardly into contact with the upwardly moving photoconductivedrum surface where the toner particles are deposited on the image areasin relation to the charge found thereon to form a developed xerographicimage. The unused developer material passes from the development zoneback into the lower portion of the developer housing where freshxerographic toner material is supplied in proportion to the amountdeposited on the drum surface from dispensing bottle 21.

Positioned next and adjacent to the developing station is the imagetransfer station D. Individual sheets of final insulating copy sheetsare fed seriatim into the sheet registering and forwarding apparatus 22from either upper feed tray 35 or lower feed tray 34. Once registered,the sheets are advanced from the register stop rolls 52, 53 into movingcontact with the drum surface. The developed image is often thenelectrostatically transferred from the drum to a copy sheet by means oftransfer corotron 24. As will be explained in greater detail below, thesheet is stripped from the drum surface and forwarded along stationarytransport 26 into fuser assembly 30.

The image bearing support material stripped from the drum surface isforwarded along stationary transport 26 into the nip between upper fuserroll 31 and lower fuser roll 32. As the roll is rotated in the directionindicated, the rolls deliver both pressure and heat energy storedtherein to the copy sheet to fix th image to the support material.

After leaving the fuser assembly, the fused copy sheet is transportedthrough a curved path into a movable guide and drive roll assembly 36.The movable guides can be prepositioned' to either feed a sheetdelivered from the fuser into upper feed tray 35 or into a dischargecatch tray 37. The machine can be programmed by means of its controllogic system to precondition the paper handling equipment to acceptsimplex copy into the upper tray 35 from which the copy is once againreprocessed as explained above, through the xerographic transfer stationto form a duplex image thereon.

The next and final station in the automatic xerographic reproducingapparatus is a drum cleaning and toner recovery station E at which timeresidual toner on the drum surface is first subjected to a coronagenerating device 39 which acts to neutralize the electrostatic bondholding the residual toner to the drum station. The residual toner onthe drum is then transported into toner cleaning and recovery housing 40where the residual is removed from the drum surface by means of a doctorblade (not shown). The removed toner is conveyed longitudinally alongthe drum surface by means of a screw conveyor and deposited in thecollecting area in housing 40. The collected toner is then transportedthrough conveyor tubes 41 back into the developer housing by means of anendless chain belt.

It is believed that the foregoing description is sufficient for thepurposes of the present application to show the general operation of axerographic reproducing apparatus employing a sheet stripping apparatusconstructed in accordance with the present invention. It should,however, be noted that in this embodiment, this unique strippingapparatus allows the transfer operation to be performed at the top ofthe xerographic drum. Because of this unique positioning, it is nowquite feasible to perform a duplexing operation in a drum-type machineusing only a minimum amount of space and with a minimum amount of paperhandling equipment. Although not shown, suitable drive means areprovided to drive the drum surface, sheet feeding mechanisms, developerconveyors and other operating mechanisms at predetermined speedsrelative to each other for the proper coordination of machineoperations.

Referring morespecifically to FIGS. 2-5, a paper support material 50 isfirst fed from either of the two supply trays 34, 35 (FIG. 1) into stopmeans 51 of sheet registering roll 52. The forward movement of theleading edge of the individual sheet is momentarily interrupted by thestops for a period of time to allow the edge of the sheet to be properlyaligned against the stop. Pinch rolls 53 are then cammed into frictiondriving contact with the sheet and through means of a control mechanismacting through gears 54 and 55 the sheet rapidly accelerated to drumspeed. Once at drum velocity, auxiliary drive means (not shown) continueto advance the sheet into contact with the drum surface so that the drumand the copy sheet move into transfer station D at the same linearspeed.

A transfer corotron 24 is positioned in the transfer station justdownstream from the point at which the paper insulating sufficientstrength on the backside of the copy sheet to attract the tonerparticles from the drum surface to the insulating material. However, thetransfer corotron also-tends to build a uniform charge overlying thenonimaged areas on the drum surface. The transfer emissions accepted bythe paper in regions overline these nonimaged areas induce a charge inthe paper opposite that found in the substrate portion of thexerographic drum. The net charge distribution, therefore, in thenonimage areas creates an electrostatic attraction which tacks thesupport material to the drum surface.

The total'charge between various copy sheets and xerographic surfacesmay vary in proportion to the total amount of nonimaged areas availablewhich can accept a charge. For instance, when the copy has relativelysmall image areas thereon, the background area is increased to therebyincrease the total electrostatic attraction between the paper and thedrum. Conversely, when large solid area portions are being developed andtransferred-there is a minimum of background area and as such the totalamount of induced electrostaticattraction between the insulatingmaterial and the drum is proportionally minimized. As can be readilyunderstood, a puffer adapted to separate copy from a drum must becapable of separating the strongest charge bond possible if it is tofunction correctly. However, maximum puffing pressures acting on sheetswith a minimum bond often time result in image smears. Furthermore,maximum puffing pressures also increase the amount of dirt produced byincreasing the amount of toner particles broadcast throughout themachine.

As the drum continues to rotate in the direction indicated, the imagebearing copy sheet, which is now tacked to the drum surface, isforwarded from under the transfer corotron 24 and the copy sheet is nowin a condition to be stripped. lnitial sheet stripping is accomplishedin the present invention ;by means of a stripper finger 25. The fingeris fabricated from a relatively thin material having nonstick oradhesive properties so that the finger will ride freely on the drumsurface in nonfriction contact therewith. As positioned in the automaticmachine, the finger is supported upon a shafti60 with the thin member insubstantially perpendicular relationship to the drum surface. As shownin FIG. 4, the finger is rotatably supported on the free end of theshaft between stationary member 61 and retaining member 62. The stripperfinger is movably supported in the shaft upon a screw 63 passing throughan elongated aperture 64 in the finger and the screw threaded instationary member 61. In assembly, the top of the elongated aperturerests upon screw 63 to support'the finger as shown in FIG. 4.

The opposite end of shaft 60 is journaled for rotation intthe sidewallsof support housing 68 and the housing, in tum, supported by mountingbracket 69 which is secured to the machine frame by screws 67 (P16. 2).Mounting bracket 69 also carries a dependent horizontal support flange70 in which is secured solenoid SOL-1. The solenoid is single actingdevice which is arranged to act in opposition to torsion spring 72.Spring 72 is coupled to shaft 60 by means of coupling member 74. A crankarm 71, is secured to one end to shaft 60 with the opposite end of thecrank pinned to actuating arm 73 of solenoid SOL-1. With the solenoiddeenergized, torsion spring 72 is allowed to assume its equilibriumposition. The spring acting through coupling 74, normally supports thefinger above the drum as illustrated in FIG. 3. Energization of solenoidSOL-1, pulls crank arm 71 downwardlyto move the stripper finger to asecond drum contacting position as shown in FIG. 2.

In operation, solenoid SOL-l is energized by means of the machine logiccircuitry (not shown) to move the stripper finger 25 down into contactwiththe rotating drum surface just prior to the arrival of the leadingedge of a copy sheet. It should be clear that the freely mounted finger,upon contacting the drum, is free to rotate about the shaft 60 so thatthe finger rides under its own weight in contact with the drum surface.The stripper finger is basically shaped in the form of a wedge and ispositioned in the machine so that the apex of the wedge moves betweenthe copy sheet and the rotating drum I which. in turn, extendslongitudinally substantially across the width of the platen. The platen78 forms the bottom of a housing 79 in which is located a vacuum chamber80 (HO. '5) which is in operative communication with vacuum port 89. Thevacuum chamber 80 is connected to a vacuum pump (not shown) throughtubing 82 connected to exhaust port 81. The top of the vacuum chamber isdescribed by an incline baffle 86 which acts to uniforrnly decrease thecross-sectional area of the vacuum chamber as you move away from theexhaust port 81. The decrease in area is related proportionally to thehead loss in negative pressure across the chamber so that asubstantially uniform pressure is maintained at exhaust port 89.

Further advancement of copy sheet 50 causes the leading edge of thesheet to contact platen 78 forward of elongated vacuum port 89. At thispoint the main body of the sheet, that is, the part of the sheet behindthe leading edge thereof comes under the influence of the vacuum beingpulled through the vacuum port 89. Sufficient negative pressure ismaintained within the vacuum chamber to lift the nonimaged side of theadvancing sheet away from the stripping finger and to hold the sheet inintimate contact with the platen as shown in H0. 3. Like the stripperfinger, the bottom surface of the platen is coated with a nonstickingadhesive material, such as tetrafluoroethylene, so as to provide asurface over which the copy sheet can readily slide.

With the copy sheet securely held against the flat platen, solenoidSOL-1 is deenergized allowing torsion spring 72 to return to itsequilibrium position thereby lifting stripper finger 25 away from thedrum surface. At this time the copy sheet is held in slidingrelationship with the flat platen 78 so that further rotation of thedrum surface advances the copy sheet along the platen towards the nextsubsequent processing station. Although the negative-pressure acting onthe sheet permits the copy sheet to be freely moved along the stationaryplaten, it nevertheless is strong enough to pull or strip theelectrostatically tacked copysheet from the drum surface. In practice,it has been found that sheets of varying bond weight and size can bereadily stripped from the top of a rotating drum surface and forwardedalong a Teflon" coated platen as herein described when the platen ispositioned about 30 to a horizontal plane adjacent to the drum surfaceand a negative pressure of between 1.5 and 2.5 inches of watermaintained at the vacuum port.

In this embodiment of the present invention, the copy sheet is forwardedbetween upper fuser roll 31 and lower fuser roll 32 of fuser assembly30. Lower fuser roll 32 is coated with an elastomeric resilient materialof a lower durometer than the coating placed on upper fuser roll 31.with the rolls placed in a cooperative pressure driving condition, asshown-in HQ. 2, contact between the roll is maintained over severaldegrees of arc. A radiant heat source 33 is placed in close proximitywith the lower fuser roll and functions to maintain the surface of theroll as a temperature sufficient to heat fuse the toner image supportedon the copy sheet. The fuser rolls are rotated so that the copy sheetbeing forwarded along platen 78 and the rolls are moving at the samelinear speed. As can be seen, with the leading edge of the sheet securedbetween the fuser rolls, the trailing edge of the sheet is free to pass,through the transfer station. Because either the trailing'edge orleading edge of the sheet is being positively driven at sometime duringthe transfer and stripping operation the present apparatus is fully ableto handle cut sheets of support material. The only limitation as to thesize sheet that can be handled by the apparatus of the present'inventionis the distance that the fuser rolls are located from the transferstation, which in practice is relatively short.

Referring once again to FIG. 5, a switch 83 is mounted within transporthousing 79 above vacuum chamber 80. Switch actuator arm 84 passesthrough the vacuum chamber and platen 78 and extends into the copy sheetpath of travel. Switch 83 functions as a sensing device to detect thepassage of a copy-sheet through the transport station. Failure of a copysheet to pass through the station at a predetermined time indicated tothe machine control circuitry that a misfeed has occurred causing themachine to be shutdown.

Although a pair of cooperating fuser rolls are disclosed in thisembodiment of the invention as a means of further forwarding the cutsheets of material. it should be quite clear to one skilled in the artthat any paper forwarding means could be utilized with equaladaptability to further advance a copy sheet leaving stationarytransport 26. For example, cooperating pinch rolls could be employed toadvance the copy sheet to a subsequent processing station located at arelatively remote position in relation to the transfer station withoutdeparting from the teachings of the present invention. While thisinvention has been disclosed with reference to structure disclosedherein, it is not confined to the details set forth. and thisapplication is intended to cover such modifications or changes as maycome within the scope of the following claims.

lclaim:

1. In a xerographic transfer device of the type wherein an insulatingsheet is electrostatically tacked to a moving image support member bymeans of a corona generating device, apparatus to remove the tackedsheet from the moving member including: i

a thin wedge-shaped finger positioned substantially perpendicular to theimage support surface of the member with 'the apex of the wedge beingarranged to lift the leading edge of the electrostatically tacked sheetfrom the member and direct the sheet away from said surface,

a stationary transport supported in close proximity to said finger tointercept the leading edge of the stripped sheet and further direct saidsheet along a predetermined path of travel,

vacuum means associated with said transport to lift said sheet directlyinto contact therewith from said wedgeshaped finger and support thesheet in intimate sliding contact with said transport.

2. The apparatus of claim 1 wherein said transport is a smooth surfacedplaten along which the sheet is capable of moving in sliding contacttherewith.

3. The apparatus of claim 2 wherein said platen is coated with anadhesive material.

4. The apparatus of claim 2 wherein the surface of the platen in slidingcontact with said sheet is covered with a coating oftetrafluoroethylene.

5. The apparatus of claim 4 wherein said platen has a vacuum portextending thereacross transverse to the direction of sheet travel, saidport being positioned behind the point at which a sheet is directed intocontact with said platen whereby the body of the sheet is pulled intointimate contact with said platen.

6. The apparatus of claim 5 having subsequent sheet advancing means toengage a sheet directed along the predetermined path of travel andfurther advance said sheet.

7. The apparatus of claim 6 wherein said wedge-shaped finger rides incontact with said moving member.

8. The apparatus of claim 7 having further means to remove said wedgefrom in contact with said member when a sheet is lifted into intimatesliding contact with said platen.

9. Apparatus for transferring a developed toner image from ahorizontally supported rotating image support including:

means to bring a sheet of insulating transfer material into synchronousmoving contact with a toner image on the rotating drum surface,

a corona generator positioned adjacent to the top of said rotating drumand being arranged to s ray the back of said sheet moving in contactwith said rum with an ion discharge of a polarity and strengthsufficient to transfer toner material from the drum surface to thesupport material,

a stripper hinge positioned adjacent said corona generating device inthe direction of drum rotation and being adapted to ride in contact withthe drum surface to move between the drum surface and the support sheetwherein the sheet is lifted from the rotating surface and directedupwardly away from said surface,

a stationary platen supported in close proximity to said stripper fingerto intercept the leading edge of the upwardly moving sheet and directsaid sheet along a predetermined path of travel,

a vacuum port extending across said platen transverse to the directionof sheet travel and being positioned behind the point on said platenwhere the leading edge of the sheet is intercepted, and

means to provide a negative pressure at the port being of sufficientstrength to lift the body of the sheet from the stripper finger intoclose sliding contact with said platen.

10. The apparatus of claim 9 wherein the stripper finger is arranged toride freely in contact with said drum surface.

H. The apparatus of claim 10 further including means to lift saidstripper finger from the drum surface when said sheet is lifted intoclose sliding contact with said platen.

12. The apparatus of claim 11 wherein the surface of said platen issliding contact with said sheet is coated with an adhesive material.

13. The apparatus of claim 12 further including subsequent sheetadvancing means to engage a sheet directed along the predetermined pathof travel and further forward said sheet.

1. In a xerographic transfer device of the type wherein an insulatingsheet is electrostatically tacked to a moving image support member bymeans of a corona generating device, apparatus to remove the tackedsheet from the moving member including: a thin wedge-shaped fingerpositioned substantially perpendicular to the image support surface ofthe member with the apex of the wedge being arranged to lift the leadingedge of the electrostatically tacked sheet from the member and directthe sheet away from said surface, a stationary transport supported inclose proximity to said finger to intercept the leading edge of thestripped sheet and further direct said sheet along a predetermined pathof travel, vacuum means associated with said transport to lift saidsheet directly into contact therewith from said wedge-shaped finger andsupport the sheet in intimate sliding contact with said transport. 2.The apparatus of claim 1 wherein said transport is a smooth surfacedplaten along which the sheet is capable of moving in sliding contacttherewith.
 3. The apparatus of claim 2 wherein said platen is coatedwith an adhesive material.
 4. The apparatus of claim 2 wherein thesurface of the platen in sliding contact with said sheet is covered witha coating of tetrafluoroethylene.
 5. The apparatus of claim 4 whereinsaid platen has a vacuum port extending thereacross transverse to thedirection of sheet travel, said port being positioned behind the pointat which a sheet is directed into contact with said platen whereby thebody of the sheet is pulled into intimate contact with said platen. 6.The apparatus of claim 5 having subsequent sheet advancing means toengage a sheet directed along the predetermined path of travel andfurther advance said sheet.
 7. The apparatus of claim 6 wherein saidwedge-shaped finger rides in contact with said moving member.
 8. Theapparatus of claim 7 having further means to remove said wedge from incontact with said member when a sheet is lifted into intimate slidingcontact with said platen.
 9. Apparatus for transferring a developedtoner image from a horizontally supported rotating image supportincluding: means to bring a sheet of insulating transfer material intosynchronous moving contact with a toner image on the rotating drumsurface, a corona generator positioned adjacent to the top of saidrotating drum and being arranged to spray the back of said sheet movingin contact with said drum with an ion discharge of a polarity andstrength sufficient to transfer toner material from the drum surface tothe support material, a stripper hinge positioned adjacent said coronagenerating device in the direction of drum rotation and being adapted toride in contact with the drum surface to move between the drum surfaceand the support sheet wherein the sheet is lifted from the rotatingsurface and directed upwardly away from said surface, a stationaryplaten supported in close proximity to said stripper finger to interceptthe leading edge of the upwardly moving sheet and direct said sheetalong a predetermined path of travel, a vacuum port extending acrosssaid platen transverse to the direction of sheet travel and beingpositioned behind the point on said platen where tHe leading edge of thesheet is intercepted, and means to provide a negative pressure at theport being of sufficient strength to lift the body of the sheet from thestripper finger into close sliding contact with said platen.
 10. Theapparatus of claim 9 wherein the stripper finger is arranged to ridefreely in contact with said drum surface.
 11. The apparatus of claim 10further including means to lift said stripper finger from the drumsurface when said sheet is lifted into close sliding contact with saidplaten.
 12. The apparatus of claim 11 wherein the surface of said platenis sliding contact with said sheet is coated with an adhesive material.13. The apparatus of claim 12 further including subsequent sheetadvancing means to engage a sheet directed along the predetermined pathof travel and further forward said sheet.